磨矿因素对黄药在硫化矿浮选过程中分布的影响

以硫含量差别较大的3种含硫的铁矿石和纯黄铁矿为试样,研究了乙基黄药和丁基黄药在矿石浮选过程中,磨矿细度、磨矿介质及后续的浮选充气对药剂分布的影响。结果表明,采用钢棒介质磨矿,矿石表面的黄药分布率低,不利于黄药在其表面的吸附,而采用瓷球介质磨矿,矿石表面的黄药分布率高,有利于黄药在其表面的吸附;充气有利于矿石吸附黄药,可以提高矿石表面的黄药分布率,但采用瓷球介质磨矿后,充气对矿石吸附黄药的影响较小;磨矿介质对于纯黄铁矿吸附黄药的影响较小。     

黄铜矿生物浸出中细菌吸附规律研究

通过研究不同矿石浓度、粒度、初始pH值下细菌浸出黄铜矿的吸附规律以及表面活性剂对细菌浸出的影响,结果发现：在浸出初始阶段,细菌吸附量随时间逐渐增加,到达稳定吸附期时,吸附在矿物表面的细菌可占到90%以上;随着浸出时间的延长,经过稳定吸附时期后细菌吸附量会有所下降。表面活性剂吐温-20的存在可促进黄铜矿的氧化溶解,提高矿物的浸出速度,但不能提高铜浸出率,高于其临界值时,吐温-20反而不利于细菌生长,抑制浸出过程。     

黄药在硫化矿浮选过程中分布的影响因素研究

对五种不同的黄药在硫化矿浮选过程中分布的影响因素进行了分析研究。以硫含量差别较大的两种铁矿石为试样,研究了不同种类黄药在矿石浮选过程中,充气、搅拌、黄药浓度及种类对其分布的影响。结果表明,黄药在矿石表面的分布率随充气时间和搅拌时间的延长而升高;在充气和不充气条件下,黄药与矿石作用后,其在矿石表面的分布率最高可达95%以上,最低为20.2%,在仅搅拌条件下,含硫低和高的矿石表面的黄药分布率最高分别为49.85%和69.76%;黄药的碳链长度越长,其吸附在矿石表面的比例越高,直链结构的黄药比支链结构的黄药更易吸附在矿石表面上;黄药的浓度越高,其吸附在矿石表面的比例越高。该研究可以给黄药废水的降解及其去除提供理论基础。     

微生物浸出过程溶质迁移及其影响因素研究

溶质迁移为微生物浸出过程中重要环节之一,反应剂、生成物和营养物在固相、液相和气相之间的传递为相间传质,是溶质迁移的主要形式。化学反应及细菌生长所需的O2和CO2是靠气体的溶解和扩散提供,细菌在矿石表面的吸附可分为初级吸附和二级吸附,研究表明矿物表面疏水性愈强,愈有利于细菌的吸附。分析认为溶质迁移方式主要包括渗流迁移、分子扩散迁移和渗流弥散迁移。将影响溶质迁移的因素分为矿堆因素和溶液因素,矿石颗粒尺寸和级配、矿堆孔裂隙率、矿堆高度、偏析和密实现象等均属于矿堆因素;喷淋强度、溶液温度、饱和率、渗流特性、酸碱度、氧化剂氧化能力等属于溶液因素。     

难处理金矿的贵液侵吞及其抑制的动力学

本文研究了难处理矿石氰化过程的贵液侵吞的动力学机理，利用人工添加Ａｕ（ＣＮ）２－的方法，对其吸附的动力学进行分析，并与易处理矿石进行比较。同时还研究了焙烧和压力氧化对贵液侵吞动力学过程的影响。研究结果表明，由于试验矿石对金的吸附速度很快，是造成所试验矿石难浸的主要原因之一。通过对矿石焙烧和压力氧化处理，可导致表面吸附活性的下降。通过对金的吸附动力学过程的分析发现，第一阶段吸附速度较快且速度变化较大，具有典型的化学吸附的特征；而第二阶段吸附速度较慢，其吸附速度与吸附量之间可表为一线性关系，证明吸附过程中没有活化能的变化或吸附中心数量的变化，因而具有多层物理吸附特征。     

铁硫氧化菌群共同脱除高硫铝土矿中的硫

自高硫铝土矿区选育得到2组铁硫氧化菌群, 用于高硫铝土矿脱硫, 利用正交实验优化铁硫氧化菌群的脱硫条件, 考察了矿石驯化对提高菌群脱硫效率的影响。SEM、XRD分析结果表明: 铁硫氧化菌群可将高硫铝土矿中的含硫矿物氧化, 自矿区酸性矿坑水中富集的菌群氧化能力高于从湿润矿石表面富集的菌群。脱硫过程中生成的沉淀物黄钾铁矾类物质是制约脱硫效率的主要因素。矿石驯化对提高脱硫率有正面作用, 矿石驯化15次后, 12天脱硫率上涨14.31%, 但脱硫率与矿石驯化次数不存在线性关系。     

用混合捕收剂浮选氧化锌矿石

云南的氧化铅锌矿石,氧化程度极高,氧化率多数超过80%,含粘土、矿泥多;不少矿山的矿石中,褐铁矿的含量大于15%。这类矿石呈土状的松散结构;氧化锌矿物表面常常被铁染呈褐色。有些矿石还含较多的铁菱锌矿。含泥多,铁染严重,正是用胺法浮选氧化锌矿所忌讳的,选矿试验的结果,     

用制粒堆浸法从铁帽型金矿中回收金银的试验

<正> 一、矿石性质湖南某硫铁矿铁帽型金矿,其矿体主要由含金褐铁矿和含金破碎带角砾岩组成。其中褐铁矿、赤铁矿、石英、高岭石等矿物占整个矿物的95％以上。矿石氧化程度深,呈蜂窝状构造。金主要为自然金,其中90％在10—75μm之间,少量金被铁锰等胶体所吸附。银以独立游离银为主,其余的高度分散     

界面润湿性调控对氧化煤浮选的促进作用

煤炭的氧化使其表面疏水性减弱,可浮性显著降低。表面活性剂通过其亲水基团作用于煤表面的极性含氧官能团能够改变其表面润湿性。本文用十六烷基三甲基溴化铵(CTAB)对氧化煤进行表面润湿性调控,通过红外光谱和润湿热测定分析了CTAB在煤表面的吸附特性及煤表面的润湿性变化,结果表明,氧化煤吸附CTAB后,煤表面疏水性增强,可浮性随CTAB吸附量增大而提高;CTAB吸附于煤的同时也吸附于矿物质,矿物质表面由亲水同样转为疏水,精煤灰分大幅提升,分别采用浮选作业前水热预处理和添加六偏磷酸钠作为灰抑制剂,浮选精煤降灰效果显著。     

黄铁矿氧化抑制行为及机理研究

利用纯矿物浮选试验研究了次氯酸钠、过硫酸铵及含钙药剂 CK等氧化剂对黄铁矿、黄铜矿可浮性的影响 ,并采用实际矿石进行了验证。根据黄铁矿的电化学性质、接触角测定和黄药在矿物表面的吸附量测定 ,分析了黄铁矿在氧化状态下受抑时的表面性质。结果表明 ,氧化剂能减小黄铁矿的接触角 ,增大亲水性 ,阻止或减少黄药在矿物表面的吸附从而使黄铁矿受到抑制。     

Bioleaching of chalcopyrite by Acidithiobacillus ferrooxidans

Acidithiobacillus ferrooxidans (A. ferrooxidans) was selected to experimentally study the effects of bacteria on the oxidation of chalcopyrite. The results indicated that A. ferrooxidans remarkably promoted the oxidation of chalcopyrite. The pH of the cell broth medium was observed to increase and then decrease during the bioleaching experiment. The number of suspended bacteria in the bio-oxidation process could be divided into three stages: the initial 4 days, in which the bacteria attached to the chalcopyrite surface and the number of suspended bacteria slightly decreased; day 5 to day 52, in which the suspended bacteria clearly increased with time and reached a maximum of 3.58 × 10⁷ cells/L on day 52; and day 53 to day 80, in which the number of suspended bacteria decreased. Other parameters such as redox potential (Eh) and iron ion concentrations increased with time. SEM micrographs showed that the cells were directly attached to the erosion pits on the smooth surfaces of the chalcopyrite. The erosion pits were similar to the bacteria in shape and size, and thus, the pits were likely products of dissolution by organic acids secreted by the attached cells. Compared to the unoxidized chalcopyrite, the elemental sulfur of the eroded chalcopyrite was clearly reduced, and the elemental oxygen was slightly increased. Moreover, a biofilm was present on the surfaces of the chalcopyrite particles. Therefore, the adherence of the cells to the mineral surfaces played a predominant role in altering the mineral appearance, which is important during the leaching of chalcopyrite.     

微生物氧化硫铁矿烧渣脱硫的研究

在硫铁矿烧渣生物脱硫的实验室试验中，研究矿浆浓度，Fe^3 浓度及pH值对游离T.f.菌浓度和脱硫率的影响。结果表明硫铁矿烧渣脱硫是T.f.菌直接作用和由细菌而产生的Fe^3 间接作用的联合结果。脱硫速率和菌种氧化活性受吸附在固相上和液相中细菌生长浓度，矿浆浓度，pH值和Fe^3 的影响。三价铁离子的添加可影响菌种活性，抑制浸出，且易在矿物表面产生沉淀，降低氧化率，经生物氧化脱硫后，硫含量降至0.33%。可达到铁精矿标准。     

Investigation of the attachment of Thiobacillus ferrooxidans to mineral sulfides using scanning electron microscopy analysis

Thiobacillus ferrooxidans is a facultatively aerobic bacteria which catalyses the oxidation of inorganic substrates; in particular mineral sulfides.The mechanism(s) for the oxidation of mineral sulfides is not completely understood. The direct oxidation mechanism involves the attachment of bacteria to the mineral surface. Scanning Electron Microscopy (SEM) was used to investigate the surface erosion of three mineral sulfide samples by the attachment of Thiobacillus ferrooxidans (DSM 583). The mineral samples; Pyrite, a chalcopyrite concentrate ('termed Chalconc) and a sample containing arsenopyrite and loellingite (FeAs₂) (termed Arsenoconc) were all mounted in resin blocks and following the addition of T.ferrooxidans the particles exhibited varying degrees of surface erosion. Erosion patterns on the surface of minerals from the chalconc and arsenoconc samples appeared to follow the crystallographic structure of the mineral species. However, no apparent erosion patterns were observed on the pyrite sample. In addition, elemental sulfur was found deposited on the surfaces of each mineral sample. Chalopyrite in the Chalconc sample exhibited preferential erosion compared with the pyrite and indicated the electrochemical nobility of pyrite. In addition, during the oxidation of the Arsenoconc sample, loellingite was seen to be have been significantly more oxidised than the arsenopyrite.The observations from the SEM suggested a greater involvement of the indirect oxidation mechanism which utilises the oxidant ferric iron than direct bacterial attachment.     

闪锌矿的生物氧化与化学氧化对比

研究了氧化亚铁硫杆菌对闪锌矿的生物氧化作用,并与Fe³⁺氧化过程进行了对比。研究表明Fe³⁺比细菌具有更高的氧化效率,但生物氧化的效率更稳定。闪锌矿生物氧化过程中氧化亚铁硫杆菌的生长经历了延迟期、指数期、稳定期和衰退期,有部分细菌吸附到了矿物表面,未发现中间物质单质硫沉淀。而闪锌矿的化学氧化过程中有大量的单质硫沉淀到了矿物表面,说明生物氧化更彻底。     

The influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore

In this paper, the influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore was investigated by different techniques, including electrode, pulp potentials, DRIFT spectroscopy and microflotation tests. In addition, the gold and sulphide recoveries were also investigate, in a laboratory-scale cell, as a function of pulp potential and reagent concentration. It was verified that the presence of oxidation products on the sulphide mineral surface demands a higher collector concentration in order to achieve a satisfactory sulphide recovery. The electrochemical behaviour of pyrite and arsenopyrite indicated that a nitrogen atmosphere can lead to a low pulp potential, which inhibits the formation of oxidation products, enhancing both the free gold and sulphide recoveries. Although copper sulphate activates even oxidised sulphide surfaces, it does not improve free gold recovery.     

The cell attachment and oxygen consumption of two strains of Thiobacillus ferrooxidans

Thiobacillus ferrooxidans is a chemolithoautotropic aerobic bacteria which derives energy for its metabolic functions through the oxidation of ferrous iron, sulfur and insoluble sulfides minerals.The attachment of Thiobacillus ferrooxidans cells to sulfide mineral surfaces was investigated to further understand the mechanism involved in the leaching of sulfide minerals. Two strains of Thiobacillus ferrooxidans (DSM 583 and ATCC 23270) grown on ferrous iron, sulfur and a chalcopyrite concentrate were investigated on three sulfide mineral surfaces; pyrite, chalcopyrite and arsenopyrite. The degree of attachment of all substrate grown cells along with contact angle measurements of both minerals and cells were determined to evaluate the effect of growth substrate and hydrophobic interactions on the attachment process. In addition, concentrations of both ferrous iron and the flotation collector potassium amyl xanthate were also studied. Whilst sulfur grown cells exhibited a higher degree of hydrophobicity, both ferrous iron and chalcopyrite grown cells showed a greater degree of attachment. This suggests hydrophobic interactions at the mineral/cell interface are not principally responsible for the attachment process. Differences in the adhesion of the two strains were also observed and suggests alternative interaction(s) between the cell and mineral surface is/are principally responsible for attachment. Increasing the concentration of ferrous iron as a growth substrate resulted in an increase in the degree of cell attachment. Correspondingly, increasing the concenrration of amyl xanthate decreased the adhesion of Thiobacillus ferrooxidans.Growth substrate, solution pH, ferrous iron, copper and cobalt ion concentrations were also investigated with respect to the oxygen consumption of the two strains of Thiobacillus ferrooxidans. Enzyme reaction kinetics were also studied allowing for determination of Km values for ferrous iron similar to those previously reported. Whilst cells grown on ferrous iron were able to oxidise the iron substrate over the range 1–200mM, cells grown on 1% sulfur were unable to oxidise similar concentrations of the iron substrate. However, following a single subculture onto ferrous iron, sulfur grown cells were able to utilise the ferrous iron substrate all be it at a decreased rate. Investigation of solution pH suggested both cultures had different optimum pH values for ferrous iron oxidation. Increasing concentrations of copper and cobalt (1–100mM) proved to decrease the rate of iron oxidation.     

Influence of the attachment of acidophilic bacteria during the oxidation of mineral sulfides

Acidophilic bacteria found in mining environments are capable of oxidising insoluble sulfide minerals. The use of these bacteria during the oxidation of various mineral sulfides has received significant commercial interest.The attachment of Thiobacillus ferrooxidans and moderately thermophilic bacteria to sulfide minerals was investigated to further understand the mechanism(s) involved in the leaching of sulfide minerals. T.ferrooxidans (DSM 583 and ATCC 23270) and four strains of moderate thermophilic bacteria, Sulfobacillus thermosulfidooxidans, (strain TH1) and Sb.acidophilus (strains THWX, ALV and YTFI) all grown on ferrous iron, sulfur and a chalcopyrite concentrate (termed chalconc) were investigated using 3 sulfide mineral systems; pyrite, a chalcopyrite concentrate (chalconc) and an arsenic containing concentrate (termed arsenoconc). The degree of attachment of all substrate-grown cells along with contact angle measurements of both minerals and cells were determined in order to evaluate the effect of the growth substrate and the hydrophobic interactions on the attachment process. The attachment of both the mesophiles and moderate thermophiles were found to be dependant on the type of growth substrate, the substrate concentration and also the type of mineral studied. Whilst sufur-grown T. ferrooxidans (DSM 583) cells exhibited a higher degree of hydrophobicity, both ferrous iron and chalconc-grown cells showed a greater degree of attachment. This suggests that hydrophobic interactions are not principally responsible for the attachment of T. ferrooxidans to mineral sutfides. However, each moderately thermophilic strain exhibited greater attachment to the mineral sulfides when cultured on either the chalconc sample or elemental sulfur and all showed greater adhesion to the pyrite and arsenoconc samples than to the chalconc sample. Separate shake flask leaching of the sulfide samples T. ferrooxidans and Sb. thermosulfidooxidans (TH1) respectively in conjunction with the results of the attachment studies suggested that the leaching of mineral sulfides was a combination of both the direct and indirect mechanisms.     

脂肪醇聚氧乙烯醚对钴矿物生物浸出的影响

通过考察脂肪醇聚氧乙烯醚(AEO_9)对细菌生长、溶浸液与矿物表面的接触角以及金属浸出率的影响,研究AEO_9对钴矿物生物浸出过程的影响。研究结果表明,添加低浓度的AEO_9对细菌的生长没有影响,但浓度过高会抑制细菌生长;添加AEO_9后,可显著减小溶液与钴矿物的接触角,溶液对矿物表面的润湿作用随AEO_9质量浓度的增加而增强;添加AEO_9能够促进钴矿物的氧化溶解,提高金属浸出率,当质量浓度为0. 40 g/L时催化效果最佳,钴浸出率可提高19. 3%,铜浸出率可提高24. 3%。     

Visualization of initial attachment of bioleaching bacteria using combined atomic force and epifluorescence microscopy

Bioleaching is the dissolution of metal sulfides, such as pyrite and chalcopyrite, by bacterial oxidation processes. It has been found that attachment of leaching bacteria to the mineral surface enhances the metal sulfide dissolution. The interaction of mixed cultures with respect to initial attachment processes has not been investigated. Therefore in this study we quantified and visualized initial colonization on pyrite by pure and mixed cultures. Strains of the genera Acidithiobacillus and Leptospirillum were tested. Sessile and planktonic cells were visualized by fluorescence microscopy using DAPI, FISH, Syto? 9, lectin- and calcofluor-staining. Additionally, atomic force microscopy (AFM) was used for the investigations on cell morphology, spatial arrangement of cells on pyrite and mineral surface topography. The morphology of planktonic and sessile cells is different. Moreover, planktonic cells show differences in morphology due to the use of different substrata. By using different visualization methods it could be proven that colonization and biofilm formation on pyrite in mixed cultures is mostly dominated by Leptospirillum spp. Interactions of different species resulted in increased production of extracellular polymeric substances (EPS) or caused bacteria showing little tendency to attach when in monoculture to be incorporated into a biofilm by those that attach preferentially. Consequently, biofilm formation and metabolic diversity were furthered. One of the most important results is the finding that not all bioleaching bacteria are involved to the same extent in biofilm formation. Thus, further work shall allow us elucidate the important bacteria for biotechnological use, thereby leaching processes can be faster, more efficient and costs can be reduced.     

Studies on the mechanism and kinetics of bioleaching

The use of off gas analysis and redox potential measurement has shown that bioleaching involves at least three important sub-processes. The primary attack of the sulphide mineral is a chemical ferric leach. The role of the bacteria is to convert the iron from the ferrous to the ferric form, thereby maintaining a high redox potential.The kinetics of bacterial ferrous iron oxidation by Thiobacillus ferrooxidans and a Leptospirillum-like bacterium, and the chemical ferric leach kinetics of pyrite have both been described as functions of the ferric/ferrous-iron ratio. Thus, the chemical ferric leach of the mineral and the bacterial oxidation of the ferrous iron are linked by the redox potential, and are in equilibrium when the rate of iron turnover between the mineral and the bacteria is balanced.These rate equations have been used to predict the steady state redox potential and sulfide mineral conversion in a continuous bioleach reactor. The model successfully predicts laboratory data and is being tested against data from pilot-plant and full-scale bioleach systems. Furthermore, the model predicts which bacterial species will predominate and which mineral will be preferentially leached under specific operating conditions. Enzyme restriction analysis has shown that in pyrite-arsenopyrite bioleach reactors the dominant iron oxidizer is L. ferrooxidans, which is in agreement with the predictions of the model.